memstick: fix hangs on unexpected device removal in mspro_blk

memstick: fix hangs on unexpected device removal in mspro_blk

commit d862b13bc8cbab9692fbe0ef44c40d0488b81af1 upstream.

mspro_block_remove() is called from detect thread that first calls the
mspro_block_stop(), which stops the request queue.  If we call
del_gendisk() with the queue stopped we get a deadlock.

Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Cc: Alex Dubov <oakad@yahoo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>